# Tunnel Gotchas

## Common Errors

### "Error 1016 (Origin DNS Error)"

**Cause:** Tunnel not running or not connected
**Solution:**
```bash
cloudflared tunnel info my-tunnel     # Check status
ps aux | grep cloudflared             # Verify running
journalctl -u cloudflared -n 100      # Check logs
```

### "Self-signed certificate rejected"

**Cause:** Origin using self-signed certificate
**Solution:**
```yaml
originRequest:
  noTLSVerify: true      # Dev only
  caPool: /path/to/ca.pem  # Custom CA
```

### "Connection timeout"

**Cause:** Origin slow to respond or timeout settings too low
**Solution:**
```yaml
originRequest:
  connectTimeout: 60s
  tlsTimeout: 20s
  keepAliveTimeout: 120s
```

### "Tunnel not starting"

**Cause:** Invalid config, missing credentials, or tunnel doesn't exist
**Solution:**
```bash
cloudflared tunnel ingress validate  # Validate config
ls -la ~/.cloudflared/*.json         # Verify credentials
cloudflared tunnel list              # Verify tunnel exists
```

### "Connection already registered"

**Cause:** Multiple replicas with same connector ID or stale connection
**Solution:**
```bash
# Check active connections
cloudflared tunnel info my-tunnel

# Wait 60s for stale connection cleanup, or restart with new connector ID
cloudflared tunnel run my-tunnel
```

### "Tunnel credentials rotated but connections fail"

**Cause:** Old cloudflared processes using expired credentials
**Solution:**
```bash
# Stop all cloudflared processes
pkill cloudflared

# Verify stopped
ps aux | grep cloudflared

# Restart with new credentials
cloudflared tunnel run my-tunnel
```

## Limits

| Resource/Limit | Value | Notes |
|----------------|-------|-------|
| Free tier | Unlimited tunnels | Unlimited traffic |
| Tunnel replicas | 1000 per tunnel | Max concurrent |
| Connection duration | No hard limit | Hours to days |
| Long-lived connections | May drop during updates | WebSocket, SSH, UDP |
| Replica registration | ~5s TTL | Old replica dropped after 5s no heartbeat |
| Token rotation grace | 24 hours | Old tokens work during grace period |

## Best Practices

### Security
1. Use token-based tunnels (config source: cloudflare) for centralized control
2. Enable Access policies for sensitive services
3. Rotate tunnel credentials regularly
4. After rotation: stop all old cloudflared processes within 24h grace period
5. Verify TLS certs (`noTLSVerify: false`)
6. Restrict `bastion` service type

### Performance
1. Run multiple replicas for HA (2-4 typical, load balanced automatically)
2. Replicas share same tunnel UUID, get unique connector IDs
3. Place `cloudflared` close to origin (same network)
4. Use HTTP/2 for gRPC (`http2Origin: true`)
5. Tune keepalive for long-lived connections
6. Monitor connection counts

### Configuration
1. Use environment variables for secrets
2. Version control config files
3. Validate before deploying (`cloudflared tunnel ingress validate`)
4. Test rules (`cloudflared tunnel ingress rule <URL>`)
5. Document rule order (first match wins)

### Operations
1. Monitor tunnel health in dashboard (shows active replicas)
2. Set up disconnect alerts (when replica count drops to 0)
3. Graceful shutdown for config updates
4. Update replicas in rolling fashion (update 1, wait, update next)
5. Keep `cloudflared` updated (1 year support window)
6. Use `--no-autoupdate` in prod; control updates manually

## Debug Mode

```bash
cloudflared tunnel --loglevel debug run my-tunnel
cloudflared tunnel ingress rule https://app.example.com
```

## Migration Strategies

### From Ngrok
```yaml
# Ngrok: ngrok http 8000
# Cloudflare Tunnel:
ingress:
  - hostname: app.example.com
    service: http://localhost:8000
  - service: http_status:404
```

### From VPN
```yaml
# Replace VPN with private network routing
warp-routing:
  enabled: true
```

```bash
cloudflared tunnel route ip add 10.0.0.0/8 my-tunnel
```

Users install WARP client instead of VPN.